多项选择题
A. CHAP uses a two-way handshake
B. CHAP authentication periodically occurs after link establishment
C. CHAP has no protection from playback attacks
D. CHAP authentication is performed only upon link establishment
E. CHAP uses a three-way handshake
F. CHAP authentication passwords are sent in plaintext
多项选择题 the network administrator has been asked to give reasons for moving from ipv4 to ipv6. what are two valid reasons for adopting ipv6 over ipv4?（）
多项选择题 Which three approaches can be used while migrating from an IPV4 addressing scheme to an IPV6 scheme.（）
多项选择题 Which two subnetworks would be included in the summarized address of 172.31.80.0 /20?（）